Botanicals impact the bifidogenic effect and metabolic outputs ofin vitrofiber fermentation by gut-derived microbiota in individual-specific ways

Abstract

Modern diets typically contain dramatically lower fiber content compared to traditional hunter-gatherer and agrarian diets, and this trend is paralleled by an enhanced frequency of chronic diseases. Despite national nutrition policy and education instructing Americans on the beneficial health value of increasing daily fiber consumption, a 'fiber gap' still persistently exists. Fortification of product groups frequently consumed by a large proportion of society provides an attractive strategy to close this 'fiber gap' and may have the potential to concomitantly reverse the detrimental health effects exacerbated by our modern diets. Besides prebiotic fibers, products can contain several other functional components, such as botanicals. However, the vast majority of studies have investigated functional components in isolation. For instance, preferential fermentation of specific prebiotic fibers by bifidobacteria has been clearly established, both in terms of their increased abundance in the gut microbiome and the elevated levels of beneficial metabolites, including short chain fatty acids (SCFAs) produced directly (acetate) or through interactions with other microbiota members (resulting in butyrate and propionate production). The impact of other components present in functional product blends on this bifidogenic effect are largely unexplored. Here, we investigated the fiber and botanical blends included in OLIPOP, a functional soda, in an in vitro gut fermentation model. Our data revealed that the blend of inulins and resistant dextrins promoted growth of bifidobacteria across gut microbiota from four donors, even those with small initial populations. In addition, botanicals interacted with fiber fermentation in donor-specific ways, in some cases strongly enhancing fermentation rate and production of SCFAs. Our data suggest that botanicals can modify the rate and microbial and metabolic fates of prebiotic fiber fermentation, and suggest that future studies should examine such interactions in greater detail.